//download.js v4.2, by dandavis; 2008-2016. [CCBY2] see http://danml.com/download.html for tests/usage
// v1 landed a FF+Chrome compat way of downloading strings to local un-named files, upgraded to use a hidden frame and optional mime
// v2 added named files via a[download], msSaveBlob, IE (10+) support, and window.URL support for larger+faster saves than dataURLs
// v3 added dataURL and Blob Input, bind-toggle arity, and legacy dataURL fallback was improved with force-download mime and base64 support. 3.1 improved safari handling.
// v4 adds AMD/UMD, commonJS, and plain browser support
// v4.1 adds url download capability via solo URL argument (same domain/CORS only)
// v4.2 adds semantic variable names, long (over 2MB) dataURL support, and hidden by default temp anchors
// https://github.com/rndme/download

function download(data, strFileName, strMimeType) {
  var self = window, // this script is only for browsers anyway...
    defaultMime = "application/octet-stream", // this default mime also triggers iframe downloads
    mimeType = strMimeType || defaultMime,
    payload = data,
    url = !strFileName && !strMimeType && payload,
    anchor = document.createElement("a"),
    toString = function (a) {
      return String(a);
    },
    myBlob = (self.Blob || self.MozBlob || self.WebKitBlob || toString),
    fileName = strFileName || "download",
    blob,
    reader;
  myBlob = myBlob.call ? myBlob.bind(self) : Blob;

  if (String(this) === "true") { //reverse arguments, allowing download.bind(true, "text/xml", "export.xml") to act as a callback
    payload = [payload, mimeType];
    mimeType = payload[0];
    payload = payload[1];
  }


  if (url && url.length < 2048) { // if no filename and no mime, assume a url was passed as the only argument
    fileName = url.split("/").pop().split(/[?&]/g).pop().replace('filename=', '');
    anchor.href = url; // assign href prop to temp anchor
    if (anchor.href.indexOf(url.replace(/\?.*$/, '')) !== -1) { // if the browser determines that it's a potentially valid url path:
      var ajax = new XMLHttpRequest();
      ajax.open("GET", url, true);
      ajax.responseType = 'blob';
      ajax.onload = function (e) {
        download(e.target.response, fileName, defaultMime);
      };
      setTimeout(function () {
        ajax.send();
      }, 0); // allows setting custom ajax headers using the return:
      return ajax;
    } // end if valid url?
  } // end if url?


  //go ahead and download dataURLs right away
  if (/^data:[\w+-]+\/[\w+-]+[,;]/.test(payload)) {

    if (payload.length > (1024 * 1024 * 1.999) && myBlob !== toString) {
      payload = dataUrlToBlob(payload);
      mimeType = payload.type || defaultMime;
    } else {
      return navigator.msSaveBlob ?  // IE10 can't do a[download], only Blobs:
        navigator.msSaveBlob(dataUrlToBlob(payload), fileName) :
        saver(payload); // everyone else can save dataURLs un-processed
    }

  }//end if dataURL passed?

  blob = payload instanceof myBlob ?
    payload :
    new myBlob([payload], {type: mimeType});


  function dataUrlToBlob(strUrl) {
    var parts = strUrl.split(/[:;,]/),
      type = parts[1],
      decoder = parts[2] === "base64" ? atob : decodeURIComponent,
      binData = decoder(parts.pop()),
      mx = binData.length,
      i = 0,
      uiArr = new Uint8Array(mx);

    for (i; i < mx; ++i) uiArr[i] = binData.charCodeAt(i);

    return new myBlob([uiArr], {type: type});
  }

  function saver(url, winMode) {

    if ('download' in anchor) { //html5 A[download]
      anchor.href = url;
      anchor.setAttribute("download", fileName);
      anchor.className = "download-js-link";
      anchor.innerHTML = "downloading...";
      anchor.style.display = "none";
      document.body.appendChild(anchor);
      setTimeout(function () {
        anchor.click();
        document.body.removeChild(anchor);
        if (winMode === true) {
          setTimeout(function () {
            self.URL.revokeObjectURL(anchor.href);
          }, 250);
        }
      }, 500);
      return true;
    }

    // handle non-a[download] safari as best we can:
    if (/(Version)\/(\d+)\.(\d+)(?:\.(\d+))?.*Safari\//.test(navigator.userAgent)) {
      url = url.replace(/^data:([\w/\-+]+)/, defaultMime);
      if (!window.open(url)) { // popup blocked, offer direct download:
        if (confirm("Displaying New Document\n\nUse Save As... to download, then click back to return to this page.")) {
          location.href = url;
        }
      }
      return true;
    }

    //do iframe dataURL download (old ch+FF):
    var f = document.createElement("iframe");
    document.body.appendChild(f);

    if (!winMode) { // force a mime that will download:
      url = "data:" + url.replace(/^data:([\w/\-+]+)/, defaultMime);
    }
    f.src = url;
    setTimeout(function () {
      document.body.removeChild(f);
    }, 333);

  }//end saver


  if (navigator.msSaveBlob) { // IE10+ : (has Blob, but not a[download] or URL)
    return navigator.msSaveBlob(blob, fileName);
  }

  if (self.URL) { // simple fast and modern way using Blob and URL:
    saver(self.URL.createObjectURL(blob), true);
  } else {
    // handle non-Blob()+non-URL browsers:
    if (typeof blob === "string" || blob.constructor === toString) {
      try {
        return saver("data:" + mimeType + ";base64," + self.btoa(blob));
      } catch (y) {
        return saver("data:" + mimeType + "," + encodeURIComponent(blob));
      }
    }

    // Blob but not URL support:
    reader = new FileReader();
    reader.onload = function () {
      saver(this.result);
    };
    reader.readAsDataURL(blob);
  }
  return true;
}
